[time-nuts] No more 60Hz! TEC Elimination
lists at ozindfw.net
Mon Jun 27 11:44:51 UTC 2011
On 6/24/2011 9:20 PM, Will Matney wrote:
> However, I should have
> said, one should never run a 60 Hz transformer, or motor, on the same line
> voltage it was rated for at a lower 50 Hz.
Most modern commodity transformers for electronic power supplies are
specified for rated performance from 47 to 63 Hz.
Most power distribution system products for use in the US I've seen are
rated at 60 ± 3 Hz though some stuff from European manufacturers is
rated at ± 2.5 Hz. I guess it's a holdover from 50 Hz specs.
The power companies seem to spec normal variation at a max of 0.1 Hz
though I understand the max offset they use by agreement for phase
adjustment is about 0.02 Hz.
A lot of large machinery has a a great deal of independence from the AC
line frequency. Even a 60 year old paper mill I did some work for had a
mechanical phase adjustment driven by large DC motors on the machines in
their line. IIRC the controls guy said they could compensate for 1 Hz
line frequency variations over 10 seconds. This was a lot faster than I
expected. Paper mills have lots of spinning mass that takes a long time
Oz (in DFW)
mailto:oz at ozindfw.net
Southlake, TX 76092 (Near DFW Airport)
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